Why 'battles' and not 'war'? Well, we know the war is already won:
1 Corinthians 15:57: But thanks be to God! He gives us the victory through our Lord Jesus Christ.
Yet still we are left behind in this world to catch up, to stand the seasons, trials and face the tests in the meantime.
The fact is only God knows what each person is facing at any given time even where we can offer similar experiences, everyone is unique and so will be their situation and their response to it.
'Common Battles' explores some of the life challenges we face as Christians, as what we sometimes also need is to metaphorically sit around the campfire like soldiers often do within the lull of war, with other Christians listening to those who have lived through various trials, Doesn't God Himself put us through various situations or at least allow these so that we may be able to relate or be of help to someone else in the future? Such sharing helps us remember we are not alone.